The present invention relates generally to water run-off collected in sheet flow into a special drain. The invention has particular utility in any construction which requires surface water from roadways, parking lots, swimming pool decks, etc. essentially be completed drained away. The open portion of the drain is placed level with, or slightly below, the ground or paved surface, so that water will flow through the opening and into the attached drainpipe, which is installed below the ground.
A variety of drains to carry away water are known. U.S. Pat. No. 3,815,213 to Evans, et al, disclosed, generally, drains which include a lower pipe section which has a longitudinal opening along on the upper side to form a slot in which a slotted grate is attached. The grate is formed by placing a pair of spaced plates, firmly attached, to either side of the longitudinal slot. Spacers, of multiple arrangements, are secured to the inside of each plate. These spacers comprise either solid cross-bars, which extend perpendicularly to the axis of the pipe, or a sinusoidal plate, which goes between the two (2) side plates. The plates and spacers were attached by traditional metallic welding processes. The grate is hot-dipped galvanized after fabrication. The grate is attached to galvanized pipe by metallic welding. The weld scar is repaired by applying a zinc-rich paint.
Since the '213 patent to Evans, there has been variations of slotted drains. In U.S. Pat. No. 5,380,121 to Schluter, it was disclosed a grate assembly that could be collapsible or expandable, in which to adjust for specific height requirements. The grate portion is welded, by traditional metallic processes, to a longitudinal slot in the lower pipe assembly. The grate portion comprises an upper grate portion and a lower grate portion, which are moveably fixed to one another. The grate portion is then metallic welded to the lower pipe assembly. The weld scar is covered with zinc-rich paint.
In U.S. Pat. No. 4,490,067 to Dahowski, the invention discloses a modular draining system which comprises a single piece of plastic extruded in the shape of a pipe during assembly. This assembly is pre-fabricated with little or no modification at the construction site.
Although there have been a number of drain structures disclosed, they suffer from a number of disadvantages. A number of prior drain structures involved welding metal grate portions to metal drain portions. Weather, chemicals and non-galvanizing after fabrication has a corrosive effect on metal, and, in time, may destroy the welded bond between the grate portion and the pipe portion, thus causing the drain system to be unstable. In an attempt to overcome this disadvantage, the '067 patent to Dahowski discloses a single piece drain assembly made of extruded plastic. The disadvantage with this invention is that it does not allow for any modification to the drain assembly for height adjustment. Also, size limitations of extruded full scale finished product would be impractical beyond small diameters.
The prior drainage systems either do not adequately address the concerns surrounding the corrosiveness of the welded bond by water and chemicals or, when attempting to address this problem, go to the other extreme, and do not allow flexibility in the assembly and construction of such a drain assembly. It is thus apparent that a need exists for an improved, drain assembly which permits flexibility in the assembly thereof, yet addressing the concerns dealing with the corrosive nature of water, chemicals and the welding bond as well as the durability of the entire system. Additionally, a system adaptable over a wide range of diameters is needed in the market place. This invention will span 4" through 18" and easily modified to go larger.